The biggest issue is with the current balance changes as reported is that currently lunar shower is (1) useless, actually harmful to have in PVE and (2) still promotes an activity Blizzard does not want us to do in PVP. So basically in an attempt to nerf the ability in PVP, they turned lunar shower into a talent only PVP boomkins will take.
Let me elaborate.
In PVE, Lunar Shower has had two uses. One, and I believe it is the primarily intended purpose, is to give you a nuke that you can use while you are on the move. Like other similar moves (scorch, aspect of the run, etc) it gives you less damage than your standard rotation but still allows you to do something. Now even in its current iteration it is somewhat weird in that at times you have to make the choice of either not using it or overwriting a superior dot on the target (for example you have a sunfire up, but moved away from eclipse when you suddenly have to change positions). In this regard, the new lunar shower is significantly worse than what we have now: basically if you elect to use it in an eclipse state when you have to move (once again: this is why the talent is there in the first place) you are going to waste eclipse energy from your more damaging attacks -- and if you are not in an eclipse, you will suddenly overwrite your superior dot. Basically, with this change, lunar shower becomes useless for the very thing it was created.
The other (probably side?) effect lunar shower has was to increase our AOE dps in multi-dotting scenarios. I believe that blizzard changed the nature of the lunar shower nerf to still enable us to multi-dot in a PVE setting, thereby leaving our AOE capabilities only slightly nerfed. The problem here is that the FIRST stack of lunar shower appears during the first sunfire and stays there for 3 seconds, and an IS-SF cycle is shorter than 3 seconds, so you will still end up cannibalizing your precious eclipse energy -- that is, unless you do not take the talent in the first place.
To sum it up, in PVE it does not serve as the "use when move" skill it was meant to be, and is actually detrimental to our AOE ability -- becoming that mandatory talent to SKIP. That can hardly be the intention of this nerf, and also carries the side effect that our only "mana saving" ability has to go for better performance.
In pvp, if you still elect to play as a boomkin, you will still have to rely on this ability as one of the very few things boomkins can do (as explained here: http://eu.battle.net/wow/en/forum/topic/2123512981).
There are other ways to curtail sunfire spamming. I believe one of the easiest solution would be is to make the initial damage portion of both spells to be not affected by mastery. Doing this would ensure that the ability would not hurt our AOE rotation and still find some use in single-target pve (at least in soloing/questing or in other mana conservation uses; the overriding of a more powerful buff would still be an issue), while the current reforge-everything-to-mastery pvp "builds" would suddenly notice a 70%+ nerf to their damage, ensuring that sunfire spam would not be so "overpowered".
Mind you, even this change would do little to help the current abysmal state of boomkin PVP, but on that front we can just hope. Hey, at one point they promised us instant starsurges with knockdown, and instant root that could be talented to affect multiple targets. As we have seen and read from the frost mages, instant aoe roots are not overpowered, just make your healer dispel (remember the arguments about the cat nerf?) The knockdown component to an instant starsurge would serve as a good way to give us breathing room against both melee and casters -- and hey, I would HAPPILY give up the current proc-based "burst" mechanic associated with the spell, and instead accept our role as a capable CC character. Anything better than the current feathery punching bags with cramped fingers.
Could have summed it up for you in 3 lines...
Now that using sunfire on the move consumes eclipse when talented via lunar shower, but not when you are not talented into lunar shower (if the way the patch notes are phrased is correct and not another bumble), don't take lunar shower, problem solved. Now you can spam moon/sunfire at will, doing less damage, and keep your eclipses for when you can stand and nuke again.
I probably should have used more words just to make that part clear.
Just kidding matey.
The point is not lost at all, and in fact, the point IS 'don't take lunar shower, it now sucks'.
And as for your desired point, that a pvp nerf is ruining pve, welcome to the last 2 years of WoW, where we have been going back and forth on this forever.
Now admittedly, using it with some foresight it is way more powerful than the others (see the sticky above), using it ad-hoc was always somewhat problematic. Now your suggested approach of "just ignore it" makes us the only caster dps without any real damage-while-moving options -- in addition to turning the current weak state of boomkin PVP to absolutely useless.
I am sorry to bore you with a relevant druid issue in the druid forums. Admittedly, though, I wrote this thread for those who care.
Glad to see another balance druid getting the future concept of boomkin (or should I say past concept, since this is exactly how moonkin was in wotlk, just with more damage)
In wotlk there was a big problem for mobile fights with boomkin dps, the more we move the more dramatic the dps loss was, this was solved by blizzard introducing the lunar showers talent.
It did solve the issue, but it did to the extent that sunfire spam became abusive and according to offcial blizzard posters "annoying".
Now what we see is the removal of moonkin mobility (yes you can still spam your dots, but the effect will be diminished greatly and will affect your normal rotation aswell in a negative way), it will hurt in PvE, not a giant nerf, but it will be noticable once we have some mobile encounters.
As for PvP this removes moonkins from arena at least, the damage of dots is ok, but the only viable comp moonkins are usefull, being the glass cannons they are, is along with affliction lock to put protection on those dots. Dispelled dots are just funny something you can see while not having aff lock in your team.
So with this gimp, the only viable offensive ability on the move will be made significantly less effective...
What about a compensating skill you might wonder?
I have already suggested, spirit walkers grace look-a-like ability for hardcasts, a cooldown to solve those mobile episodes in encounters, and yes, lunar showers wil be a no-no talent for PvE moonkins...
All-in-all this looks like another nerf to PvP, taking its toll on PvE aswell, result - even worse dps.
When thinking about the class and spec, I tend to consider it 'broken', obviously not as a whole, but when we excell in one way or another through PvE or PvP, the nerfbat is brought out. I am in no way indicating that I expect Balance to be some sort of 'faceroll' spec, but I'm tired of reading these patch notes from time to time, noticing that the dev's clearly don't spend as much time or consideration to this spec in comparison to others.
Oh wait, they are all bear nerfs. Never mind.
ALthough i think blizzard should just balance the friggin game on pvp sbecause by looking at forums it seems that is all ppl QQ about now days. And then i can just go roll the more OP PvE class after the "balance"
Catch a wake up blizz really.
2) Nerf initial moonfire damage within eclipse (to prevent sunfire spam)
3) Reduce cast time of wrath\starfire\starsurge (to finally buff single target damage, and let us cast in PVP)
Edit: Forgot! WTB ability similar to Shamanistic Rage, buff Owlkin Frenzy with 30% damage reduction, pretty pretty please :)
Or the owlkin frenzy talent becomes an on use skill with a 1 minute cd that also reduces damage taken by 10%/20%/30% and stacks with barskin.
The damage increase does not need you to be struck anymore.